Serial printing machine

ABSTRACT

A serial printing machine having a platen and a print carriage, head assembly having a type wheel with a plurality of lines of type, means for moving the type wheel vertically with respect to the platen to select the desired line of type and means for moving the type wheel horizontally to select the desired character; a pair of endless ribbons which are selectable so that only one of them is in printing position between the type character and the platen at any particular instant; a holding coil positioned such that when current flows in the coil, the type hammer is held out of contact with the type wheel; a pair of rails of high magnetic permeability running laterally, essentially parallel to the platen, a plurality of series connected coils wound around high magnetic permeability supports between the rails such that when current flows through the coils, a magnetic field is established which stores potential energy in the type hammer assembly; when the current in the holding coil is turned off and the potential energy is released, the type hammer moves into percussive contact with the type wheel to thereby cause the selected character to be printed.

United States Patent Kapp 1 Oct. 3, 1972 [541 SERIAL PRINTING MACHINE Primary ExaminerEdgar s. Burr 72 Inventor: Ludwig J. Kapp, Montville, NJ. Durham pm [73] Assignee: l/Q Devices, Inc., Montville, NJ. [57] ABSTRACT [22] Filed: Feb. 4, 1970 A serial printing machine having a platen and a print carriage, head assembly having a type wheel with a [211' Appl' 8617 plurality of lines of type, means for moving the type wheel vertically with respect to the platen to select the [52] US. Cl. ..197/55, 197/49, 197/ 18, desired line of type and means for moving the type 178/34 wheel horizontally to select the desired character; a [51] Int. Cl. ..B4lj l/40 pair of endless ribbons which are Selectable so that [5811, Field of Search ..l97/l8, 51, 55, 49; 178/34 only one of them is in printing position between the type character and the platen at any particular instant;

[ 5 References Cited a holding coil positioned such that when current flows in the 0011, the type hammer is held out of contact UNITED STATES PAT NTS with the type wheel; a pair of rails of high magnetic permeability running laterally, essentially parallel to 3 gzgg g l g 4 the platen, a plurality of series connected coils wound 3295652 H1967 S x around high magnetic permeability supports between 3243 7 1958 "197/49 x the rails such that when current flows through the S agerson "178/34 X coils, a magnetic field is established which stores 3308917 3/1967 ta enau et 97/49 potential energy in the type hammer assembly; when 3,543,906 12/1970 Hladky the current in the holding coil is turned off and the 3,366,214 l/1968 Tutert et al. ..l78/34 x potential energy is released, the type hammer moves 2951439 9/1960 Stutz et al l0l/l09X into percussive contact with the type wheel to thereby l alckerson cause the selected character to be printed. eans 1 Claim, 18 Drawing Figures I09 2 l 36 233" 3a 26 ,w 1 Ill gal 44 in E :5

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L UDWIG J. KAPP HIS ATTORN S SERIAL PRINTING MACHINE The invention relates to serial printing machines and in particular to those machines which are used to print out from computers.

The so-called print out machine is usually controlled by high speed electronic circuits and the printing speed is a function of the slowest mechanical element of the machine. These printing machines are generally of two types: first, those in which the platen moves laterally across the width of the machine and the print carriage, head assembly is stationary; and second, those in which the platen does not move laterally and the print carriage, head assembly moves laterally along the platen. The second type of serial printing machine is faster because the platen is heavier and more massive than the head assembly and it therefore takes longer between strokes when the platen is moved that when the head assembly is moved.

To increase the printing speed of the machine in which the head assembly moves, every effort must be made to make the assembly lighter without comprising or adversely affecting the printing quality. This can be accomplished by utilizing cooperating elements on the nonmoving portions of the machine to actuate elements on the head assembly.

It is also desirably to be able to utilize one of a number of lines of type interchangeably while printing at high speed. To accomplish this conveniently, it is necessary to use a print or type wheel which contains a number of lines of type which are readily available on command of the operator. Ideally, the type wheel should have a plurality of these lines of type, each of which contains a plurality of characters.

Mass of the print carriage, head assembly can be further reduced by utilizing endless ribbons which can be reinked after they have passed beyond the printing station and before they reach the printing station again. By using a pair of such ribbons, one is able to use different ink colors or to double the down time for ribbon changing by using two ribbons with the same ink color. By reinking the ribbon during each cycle, it is possible to use ribbons of shorter length than is possible with ribbons which are not reinked during use.

Print carriage, head assembly mass can be still further reduced by utilizing hammer actuating means located on the fixed portion of the machine rather than on the print carriage, head assembly.

Broadly, the invention comprises a platen-type, serial printing machine wherein the platen does not move laterally of the machine, the machine having a print carriage, head assembly which moves parallel to the platen. The head assembly carries a type or print wheel which is generally cylindrical in shape and upon which are the type fonts to be printed. There is a plurality of lines of type on the type wheel, preferably in rows around the type wheel with each line at a different level from the other lines. The type wheel is mounted on a shaft which rotates to select the desired character and which moves longitudinally in a direction substantially perpendicular to the plane of rotation of the type wheel to select the desired line.

A pair of endless ribbons are mounted on the head assembly in conjunction with a selecting means which moves the desired one into position between the character on the type wheel and the platen. The ribbons are reinked after moving from the printing position and before again arriving at the printing position.

The hammer is mounted on the print carriage, head assembly and is held out of contact with the print wheel by a holding solenoid. When the current is turned off momentarily, the hammer is released and moves toward the type wheel and strikes it sharply. This action pushes the desired character against the ribbon and makes an impression on the medium (such as paper) which is on the platen. To reduce weight, a large part of the hammer actuator is mounted on the frame of the printing machine rather than on the print carriage, head assembly.

The hammer actuator comprises a pair of spaced rails of high magnetic permeability material which run essentially parallel to the platen and which are mounted on the frame of the machine. The rails are held in spaced relationship by a plurality of longitudinally spaced holding elements of high magnetic permeability material. A coil is wound over each holding element and the coils are connected in series. The hammer is mounted on a flexible arm which pivots between the holding position and the striking position and is provided with a pole piece which travels along the rails and pulls up toward the coil when current is flowing in the coil thereby storing potential energy in the flexible hammer arm. The arm is kept in the retracted position until it is released by turning off the current in the holding electromagnet.

The rails extend downwardly from the coils so that a very long, horseshoe magnet is formed when current flows in the coils. The coils are spaced so that sufficient magnetic force is applied to the hammer pole piece regardless of the lateral position of the print carriage, head assembly in the machine.

It is an important object of the invention to provide a serial printing machine which may be used for rapid print out of a computer.

It is a further object of the invention to provide such a machine in which the print carriage, head assembly moves laterally across the machine with respect to the platen and the platen is in fixed lateral position in the machine.

It is a still further object of the invention to provide such a print carriage, head assembly in which the type wheel rotates about an axis which is not in the plane of the platen to select the desired character and moves in a direction perpendicular to its plane of rotation to select the desired line or level of type.

It is a still further object of the invention to provide such a print carriage, head assembly in which the type wheel is mounted on the shaft which rotates to select the desired character and which moves longitudinally to select the desired line or level of type.

It is a still further object of the invention to provide such a print carriage, head assembly in which the shaft which rotates the type wheel to select the desired character is hollow and another shaft is moved longitudinally inside this hollow shaft to select the desired line or level of type.

It is a still further object of the invention to provide such a print carriage, head assembly in which the means for rotating the type wheel is a motor and the means for moving the shaft longitudinally is a motor.

It is a still further object of the invention to provide such a print carriage, head assembly wherein the means for rotating the type wheel is a motor and the means for moving the shaft longitudinally is a solenoid.

It is a still further object of the invention to provide a print carriage, head assembly which carries a pair of endless ribbons and including means for selecting either of the ribbons for interposition between the desired character and the platen.

It is a still further object of the invention to provide a serial printing machine having a platen, a pair of rails mounted in the machine and running substantially parallel to the platen, a plurality of series-connected coils mounted between the rails so that when current flows in the coils the rails become a long, horseshoe magnet and serve to move the hammer mounted in the print carriage, head assembly so as to strike the type wheel and print the desired character.

It is a still further object of the invention to provide such a hammer actuating mechanism which includes means for adjusting the force with which the hammer strikes the type wheel.

These and other objects, advantages, features and uses will be apparent during the course of the following description, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side elevational view, partly in section, of a print carriage, head assembly of the invention, shown actual size;

FIG. 2 is a vertical end view of the upper portion of the print carriage, head assembly of FIG. 1, shown twice actual size;

FIG. 3 is a plan view, partly broken away, of the type head used with the print carriage, head assembly of FIG. 1, shown four times actual size;

FIG. 4 is a sectional view taken along the lines 4-4 of FIG. 2, viewed in the direction of the arrows, shown twice actual size;

FIG. 5 is a side elevational view of an alternative construction for selecting the type font and the character which may be used with the print carriage, head assembly of FIG. 1, shown twice actual size;

FIG. 6 is an end elevational view of the cam used with the font selection motor of FIG. 5, shown twice actual size;

FIG. 7 is a side elevational view of another alternative construction for selecting the type font and the character which may be used with the print carriage, head assembly of FIG. 1, shown twice actual size;

FIG. 8 is a side elevational view of still another alternative construction for selecting the type font which may be used with the print carriage, head assembly of FIG. I, no scale is shown;

FIG. 9 is a plan view of a stator lamination used in the embodiment of FIG. 8;

FIG. 10 is an opened up view, in plan, of the stator used with the embodiment of FIG. 8;

FIG. 11 is an opened up view, in plan, of the movable armature used with the embodiment of FIG. 8;

FIG. 12 is a side elevational view, partly in section, of the ribbon drive mechanism used with the print carriage, head assembly of FIG. 1, shown four times actual size;

FIG. 13 is a side elevational view, partly broken away, of the ribbon feed mechanism used with the print carriage, head assembly of FIG. 1, shown twice actual size;

FIG. 14 is a top view of the ribbon feed mechanism used with the print carriage, head assembly of FIG. 1, shown twice actual size;

FIG. 15 is a vertical, front view, partly cut away, of the ribbon feed mechanism used with the print carriage, head assembly of FIG. 1, shown twice actual size;

FIG. 16 is an elevational view of the impression control used with the print carriage, head assembly of FIG. 1 in the darkest position, shown twice actual size;

FIG. 17 is a view similar to that of FIG. 16 showing the same impression control in the lightest position, shown twice actual size; and

FIG. 18 is a side elevational view of the hammer and associated parts used with the print carriage, head assembly of FIG. 1, shown twice actual size.

In the drawings, wherein, for the purpose of illustration, there are shown, preferred embodiments of the invention, the numeral 20, designates a print carriage, head assembly used with a serial printing machine of the invention.

Print carriage 20 is driven laterally across the machine with respect to platen 22 by means of drive shaft 24 and is supported at its front by laterally extending rails 26. Type wheel 28 contains several lines or rows of characters and is rotated and moved up and down to select the desired character by its support shaft 40 and the ball and socket assembly 38.

Character selection is accomplished by rotating type wheel 28 into the proper location with respect to the platen 22. The type wheel rotation is controlled by motor 52 and its hollow rotor shaft 30, to which the housing 38 and selection disk 54 are attached. As the housing 38 turns, it controls at the same time the rotational positioning of the ball and socket assembly 38 and the mounting shaft 40.

Character selection is sensed by means of character selection disk 54 and two photoelectric cell assemblies 56 (one of which is shown in FIG. 2 and both of which are shown in FIG. 4). By utilizing a pair of photoelectric cell assemblies and a logic control circuit (details not shown), it is possible to arrange the system so that the rotation of character selection motor 52 will never be greater than The longitudinal movement of the ball and socket assembly 38 is controlled by the inner shaft 32. The motion is generated by means of rotating motor 36, its hollow rotor shaft 36' and the attached driver 36". The rotational movement is further transmitted to a screw 32', which can slide up and down on the driver unrestricted as it turns. The longitudinal position of screw 32' is controlled by a screw nut 34 adjustably attached to the frame of print carriage 20. As the screw 32' is turned it follows the screw thread up and down. Screw 32 is fixed to the lower end of shaft 32. The shaft extends then upwards through both hollow motor shafts 36 and 30 and its upper terminal is the ball 38" of the ball and socket assembly 38.

At the same time as the socket assembly 38 is turned by housing 38' it is moved longitudinally by the ball 38". This in turn serves to place the desired type in alignment with the selected ribbon and platen 22.

The type line or level is selected by means of selection disk 42 and photoelectric cell assembly 44. The

level selection disk is suitably slotted so that its position may be sensed by the photoelectric cell assembly 44.

During the non-printing mode of the'machine, screw 32' will always be moved down into its lowest position, and in turn, the printwheel will be out of alignment with the platen to give the operator an unobstructed vision of the printing.

To prevent rotation of the type wheel 28 during the percussion portion of the printing cycle a locking arm 58 is biased into the tooth space 62 as the printwheel is moved towards the platen. The detent is part of the serrated internal surface of type wheel 28. A toroid spring 60 will insure the proper home positionof print wheel 28 between printouts with sufficient clearance between locking arm 58 and the top of the serration 64 for the rotational motion (as shown in FIG. 3).

In addition, a quick connector 28' on the print wheel permits the operator to change the print wheel instantaneously for a greater selection of type fonts.

In FIGS. 5 and 6 there is illustrated an alternative embodiment for positioning the print wheel to select a character. Motor 52 rotates shaft (which is a hollow tube) in conjunction with character selection disk 54 as has been described previously. Motor 66, which is the level selection motor, is mounted substantially perpendicular to the longitudinal dimension of shaft 30. It operates inconjunction with level selection disk 42 and photoelectric cell assembly 44 for level selection by moving shaft 32 longitudinally.

Motor 66 is provided with a shaft 67 on the end of which there is mounted a cam housing 68. Cam housing 68 is provided with cam race 69 in which cam follower 70 rides. As motor 66 rotates, as controlled by selection disk 42, cam follower 70 is moved in race 69 to thereby raise and lower type wheel 28 due to the longitudinal movement of shaft 32.

In FIG. 7, there is illustrated still another embodiment of a construction for moving shaft 32 longitudinally to select the appropriate type line.

Motor 52 rotates hollow shaft 30 to rotate the type wheel for character selection. Shaft 32 is moved longitudinally by electromagnetic solenoid 72. Armature 74 is moved within solenoid 72 and acts in conjunction with spring 76 to move shaft 32 longitudinally. The level position of the type wheel is sensed by sensors 78 and 80 has its position controlled by sensing circuit 82. The upward movement of the solenoid plunger is a function of the current through the solenoid. A certain level is given as an equilibrium between the force produced by the solenoid and the force opposing it as a result of the compression of the spring. The current output of the amplifier is a function of the desired level.

Still another embodiment of line selection means which may be used with the machine of the invention is shown in FIGS. 8-11. Shaft 32 is connected to cupshaped, cylindrical armature 84 which is formed of magnetic material and is provided with a number of apertures 86 as shown in FIG. 11. FIG. 11 is an unfolded view of the armature 84.

Stator 88 is formed of laminations of magnetic material such as is illustrated in FIG. 9 and is designated, as 90. Laminations 90 are provided with projections 92 and the laminations are stacked as shown in the unfolded view of FIG. 10.

When the stator laminations are stacked, the individual projections 92 form winding guides for the coils 94, 96, 98 and 100 and, when current flows, form magnets 102 which attract the magnetic elements 86 to raise and lower armature 84. Sensing of the longitudinal position of shaft 32 may be accomplished in the same manner as has been described for the embodiment of FIG. 7.

The machine illustrated and described herein utilizes two endless ribbons 104, one of which is selected for interposition between a selected character and the paper on the platen. During no print cycles of the machine both ribbons are in a down position for an unobstructed view of the printing. The ribbon is lifted into printing position by two rods 119 located at each side of the print carriage and cooperate with guide slots 118 of guides 110. Every time shaft 32 and its extension 32 is moved up into a printing position it allows arm 46, which is pivoted at 48 and biased upwards by spring 50, to follow and in turn lift rods 119.

The ribbons are driven by drive wheel 109 which has a friction coated circumference. The drive wheel is actuated through the clutch which is mounted to frame 20 and which is comprised of hub elements 112 and 114 and spring 116 and activating arm 108. The activating arm 108 of the ribbon drive 109 functions like the weight in a self-winding watch. While the print carriage is accelerated, the pivoted weight lags behind, and when the carriage is being decelerated, the weight keeps moving'and the one way spring clutch 116 grips and turns the ribbon drive hub 109.

The ribbons are driven by ribbon drive 109 in a closed circuit which includes ribbon drive wheel 109 and ribbon inking mechanisms 120. Each ribbon is inked by the appropriate inking mechanism 120 and is inked in the course of its travel between its leaving the position wherein it is between the type wheel and the platen and its arriving in that position for the next time. Inking is accomplished by the ribbons pressing against the ink retaining element in the inking mechanism. To replenish the ink supply, the reinking roller of the ribbon inking mechanism can easily be replaced by swinging the tension arms pivoted at 120' against limit stop 121. The same procedure has to be followed if a ribbon should be replaced.

The second ribbon can be selected by activating solenoid 106. Rods 119 cooperate then with guide slots 118, of ribbon guide 110'. In the center position neither ribbon moves up, this position is called the stencil position.

Print carriage, head assembly 20 rides on rails 26 by means of rollers and 131. The position of the rollers with respect to the rails is adjusted by means of offcenter screw 132. Rails 26 are held in spaced relationship by a plurality holding means shown in FIG. 1 as screw 127. The screws are preferably of magnetizable, high permeability material and a coil 128 is wound around each of them. These coils are spaced along the rails and are connected in series. The rails 26 depend downwardly, as shown in FIG. 1 to form an elongated horseshoe magnet extending laterally of the machine.

Holding solenoid 123 holds hammer 122 in its first position, out of contact with the type wheel. Now, when current flows in the coils 128, pole piece 126 is drawn upward toward rails 26 but is prevented from touching the coil or rails by stop 133. The holding solenoid 123 holds the hammer away from the print wheel. When the current is turned off in holding solenoid 123, the bifurcated hammer arm 124, (which is a leaf spring) moves to its second position (in contact with the type wheel). This construction is best seen in FIG. 15. The percussive force impresses the selected character against the ribbon and in turn prints the selected character on the paper on the platen 22. The current in the magnetic rail solenoids stays on during that period but is turned off prior to applying current to the holding solenoid to catch the returning print hammer. Then, the cycle is repeated to restore the potential energy in the spring.

The strength of the impression is controlled by impression control arm 134 which fits in the notches in element 136 and serves to lengthen or shorten the pivot distance of arm 124. In FIG. 16, the impression is the darkest and in FIG. 17, it is the lightest. In FIG. 1, the impression control is in an intermediate or normal position.

In FIG. 18, there is illustrated another embodiment of hammer assembly which may be used in machines of the invention. Rails 142 form an elongated horseshoe magnet with its poles pointed upward. Rollers 130 and 131 and off center screw 132 operate as has been previously described. Holding means 127 and coils 128 operate in conjunction with rails 142 as they did in conjunction with rails 26.

When current flows in coils 128, pole piece 148 is drawn toward rails 142 and is prevented from touching them by stop 149. This stores potential energy in the system by placing spring 146, which is wound around pivot 147, in tension. The current in holding coil 140 is turned on. Now, the current in coils 128 is turned off but the arm 144 will not move forward until the current in coil 140 is turned off. When the current in holding coil 140 is turned off, the hammer 138 moves from its first position (out of contact with the print wheel) to its second position (in percussive contact with the print wheel).

Operation of the machine, including line selection, character selection, ribbon selection, and hammer actuation may be controlled from a computer output or from a manually or automatically operated keyboard or from punched or magnetic tape in any manner which is well-known in the art. It only being sufficient that the appropriate signals and voltages be applied, as

required.

While particular embodiments of the invention have been shown and described, it is apparent to those skilled in the art that modifications are possible without departing from the spirit of the invention or the scope of the subjoined claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a print carriage head assembly for a serial printing machine having a frame and a type wheel mounted in the head assembly frame for rotating around an axis. said type wheel having a plurality of lines of type and a plurality of characters in each line, the improvement which comprises:

a shaft having two ends, one end of which is connected to the type wheel;

a hollow tube around said shaft motor means for rotating said hbllow tube;

means intermediate said hollow tube and said shaft for rotating said shaft when said hollow tube is rotated for rotating said type wheel to selected character positions; and

means for moving said shaft axially through said hollow tube for moving said type wheel to selected desired type line positions, said moving means including means connected to the other end of said shaft;

said means for moving said shaft axially through said hollow tube and for moving the type wheel to the desired line selection position includes:

an armature, which is generally cup-shaped and is formed of nonmagnetizable material, affixed to said shaft;

a plurality of elements of magnetizable material affixed to the armature in a predetermined, space pattern;

a laminated stator mounted within the cup shaped armature;

a plurality of coils wound on the stator in a predetermined pattern and connected such that when current flows in a predetermined one of the said coils, the magnetizable elements affixed to the armature are attracted by the established magnetic field and moved to a predetermined position with respect to the stator to thereby move the type wheel to select the desired type line. 

1. In a print carriage head assembly for a serial printing machine having a frame and a type wheel mounted in the head assembly frame for rotating around an axis, said type wheel having a plurality of lines of type and a plurality of characters in each line, the improvement which comprises: a shaft having two ends, one end of which is connected to the type wheel; a hollow tube around said shaft; motor means for rotating said hollow tube; means intermediate said hollow tube and said shaft for rotating said shaft when said hollow tube is rotated for rotating said type wheel to selected character positions; and means for moving said shaft axially through said hollow tube for moving said type wheel to selected desired type line positions, said moving means including means connected to the other end of said shaft; said means for moving said shaft axially through said hollow tube and for moving the type wheel to the desired line selection position includes: an armature, which is generally cup-shaped and is formed of nonmagnetizable material, affixed to said shaft; a plurality of elements of magnetizable material affixed to the armature in a predetermined, space pattern; a laminated stator mounted within the cup shaped armature; a plurality of coils wound on the stator in a predetermined pattern and connected such that when current flows in a predetermined one of the said coils, the magnetizable elements affixed to the armature are attracted by the established magnetic field and moved to a predetermined position with respect to the stator to thereby move the type wheel to select the desired type line. 